I had 2 badly oversize HX chambered .45 colts. I kept sending them back and finally got a HY chamber that is spot on. I can unload and directly drop the fired brass into my Blackhawk. Depending on the support where you got it, might want to fight for a better one. The .454 is only .002 larger diameter if I understand correctly, so if it is large enough to not chamber in your Ruger, reaming to .454 probably won't cut it. 8( If it's in that .002 range, .454 might be the fix, but your Colt brass, if you shoot them, will also blow out still. 8(